SaaS exfiltration is the unauthorized copying or downloading of data from software-as-a-service platforms such as email, file sharing, CRM, ticketing, or collaboration tools. Because these services store business-critical records in the cloud, a single compromised account or stolen session token can give an attacker broad access without deploying malware on endpoints.
This matters because modern intrusions often look like normal user activity: logins from unfamiliar locations, mass file downloads, mailbox exports, API pulls, or sharing changes that expose private folders. Defenders look for these patterns with audit logs, anomaly detection, least-privilege access, phishing-resistant MFA, and alerts for bulk export behavior. In practice, SaaS exfiltration is a common end stage of identity-based attacks, where the attacker uses valid credentials to quietly remove data before anyone notices.